TW201727440A - Optical touch sensing system, optical touch sensing device and touch detection method thereof - Google Patents

Abstract

An optical touch sensing system, an optical touch sensing device, and a touch detection method thereof are provided. The optical touch sensing system includes an optical touch sensing device and a stylus. The optical touch sensing device includes a touch panel, multiple optical sensors, a first light source and a processor. The touch panel has a touch surface. The first light source produces a first light periodically. The stylus includes a switch module and a second light source. The switch module lets the second light source produce a second light when the stylus is touched the touch surface. The processor determines a position touched by the stylus according to the first light and the second light received by the optical sensors.

Description

Optical touch system, optical touch device and touch detection method thereof

The present invention relates to an optical touch technology, and more particularly to an optical touch system, an optical touch device, and a touch detection method thereof.

Screen touch technology has been widely used in a variety of consumer electronic devices, allowing users to intuitively select objects on the screen to achieve control effects. In the past touch technology, the capacitive touch screen has the best touch effect, but the cost is also the most expensive. Among other touch technologies, an optical touch screen that uses an optical lens to detect a touch position has the advantages of low cost, high accuracy, and the like, and has become an alternative to a large-size touch screen.

The optical touch screen uses a plurality of optical lenses on the edge of the screen to analyze the image of the user's finger on the screen to analyze the image being blocked by the touch object (eg, a stylus). The generated data, combined with the triangulation method, is used to calculate the exact position of the touch point. However, although the optical lens has been placed as close as possible to the touch screen, there is still a gap between the image capturing surface of the optical lens and the touch surface. In some use cases, for example, using a touch object (stylus) to write on the touch screen, if the user does not raise the stylus a sufficient distance relative to the touch screen between each stroke If the distance between the touch object and the touch screen is not far enough, it will be judged that the stylus still touches the touch screen. Excessive connection lines will be generated between the stroke and the stroke, so that the screen is not expected by the user. Image. Therefore, how to judge whether the stylus actually touches the touch screen in the optical touch technology is still a problem that needs to be improved.

The invention provides an optical touch system, an optical touch device and a touch detection method thereof, which can accurately detect the timing at which the stylus touches the touch panel, thereby determining the position touched by the stylus.

The invention discloses an optical touch system. The optical touch system includes an optical touch device and a stylus. The optical touch device includes a touch panel, a plurality of optical sensors, a first light source, and a processor. The touch panel has a touch surface. The first light source periodically generates a first light. The processor couples the optical sensor and the first light source. The stylus includes a switch module and a second light source. The switch module is coupled to the second light source. When the stylus touches the touch surface, the switch module causes the second light source to generate a second light. The processor determines the position of the stylus according to the first light and the second light received by the optical sensor.

The invention discloses a touch detection method of an optical touch device. The optical touch device includes a touch surface. The touch detection method includes the following steps. The first light is generated periodically. It is determined whether the estimated touch position is obtained based on the first light. After obtaining the estimated touch position, determining whether to receive the second light during the next disable period of the first light source, wherein the second light is generated by the stylus when the touch surface is touched . If so, it is determined that the estimated touch position is the position touched by the stylus.

The invention discloses an optical touch device. The optical touch device includes a touch panel, a plurality of optical sensors, a first light source, a light source generating module, a touch position determining module, and a contact determining module. The touch panel has a touch surface. A light source generating module controls the first light source to periodically generate a first light. The touch position determining module determines whether the estimated touch position is obtained according to the first light. The contact determination module is coupled to the touch position determination module. After obtaining the estimated touch position, the contact determination module determines whether to receive the second light during the next disable period of the first light source, wherein the second light is generated by the stylus when the touch surface is touched . If yes, the contact determination module determines that the estimated touch position is the position touched by the stylus.

The invention discloses an optical touch system, which comprises a touch panel and a stylus. The optical touch device includes a touch panel, a plurality of optical sensors, a first light source, and a processor. The touch panel has a touch surface. The first light source periodically generates a first light. The processor couples the optical sensor and the first light source. The stylus includes a switch module and a second light source. When the switch module is pressed, the second light source generates a second light. The processor determines a position of the stylus according to the first light and the second light received by the optical sensor.

The invention discloses a touch detection method for an optical touch device, wherein the optical touch device comprises a touch surface. The touch detection method includes the following steps. The first light is generated periodically. Whether or not the estimated touch position is obtained is determined according to the first light. After obtaining the estimated touch position, determining whether to receive the second light during the next disable period of the first light source, wherein the second light is generated when the switch module of the stylus is pressed . If so, it is determined that the estimated touch position is the position touched by the stylus.

The invention discloses an optical touch device. The optical touch device includes a touch panel, a plurality of optical sensors, a first light source, a light source generating module, a touch position determining module, and a contact determining module. The touch panel has a touch surface. A light source generating module controls the first light source to periodically generate a first light. The touch position determining module determines whether the estimated touch position is obtained according to the first light. The contact determination module is coupled to the touch position determination module. After obtaining the estimated touch position, the contact determination module determines whether to receive the second light during the next disable period of the first light source, wherein the second light is generated when the switch module of the stylus is pressed. . If yes, the contact determination module determines that the estimated touch position is the position touched by the stylus.

Based on the above, the optical touch system, the optical touch device and the touch detection method thereof are firstly determined by the first light on the optical touch device to determine whether the estimated touch position is obtained. After obtaining the estimated touch position, the optical touch device determines whether the stylus actually touches the touch panel by using the second light emitted from the stylus during the next disable period of the first light source. The second light may be generated when the stylus touches the touch panel, or may be generated when the user presses the switch module on the stylus. In this way, the optical touch device can detect whether the stylus actually touches the signal of the touch panel by detecting the second light or not, thereby assisting to determine whether the estimated touch position is indeed the stylus The actual location of the touch. In addition, the brightness of the second light can be adjusted to be lower than a preset threshold of the optical touch device to achieve power saving.

The above described features and advantages of the invention will be apparent from the following description.

1 is a schematic diagram of an optical touch system 100 in accordance with an embodiment of the present invention. The optical touch system 100 includes an optical touch device 110 and a stylus 120. The optical touch device 110 includes a touch panel 150 , at least two optical modules 130 , and a processor 140 . In this embodiment, each optomechanical module 130 can include an optical sensor (eg, an infrared camera) and a first light source. The touch panel 150 includes a touch surface 160.

In some embodiments, the first light source may be independent of the light machine module, and the number of the first light sources may be single or multiple. In other words, the third light ray L3 is the light that reflects the first light ray L1 from the stylus. In this embodiment, the first light source is a light emitting diode unit that emits infrared light, and the first light source is controlled by the processor 130 to emit a first light (eg, infrared light) intermittently or periodically. Applicants of the present embodiment can appropriately adjust the placement position of the optical module, the optical sensor, and the first light source, for example, separating the optical sensor from the first light source and setting the optical touch device 110 differently. Location...etc.

The first light source may not be limited to an infrared light source, but may be a visible light source, other invisible light sources (eg, ultraviolet light), or a laser light source. In the embodiment of the present invention, in order to prevent the light from glare to the user and reduce the influence of ambient light, an infrared light source that is invisible to the naked eye is selected as the first light source, and the first light L1 generated by the light is infrared light. The optical sensor of the optical module 130 can be matched with the above-mentioned infrared light filter to filter out unnecessary wavelength light to reduce ambient light interference. The infrared light has a wavelength between 760 nanometers (nm) and 1 millimeter (mm). The processor 140 may be a central processing unit (CPU), a microprocessor, or an application-specific integrated circuit (ASIC), and the embodiment of the present invention is not limited thereto.

The processor 140 is coupled to the touch panel 150, the optical sensor in the optomechanical module 130, and the first light source. The optical sensors are driven by the processor 140 to obtain optical images on the touch surface 160 of the touch panel 150 and transmit the optical images back to the processor 140. The processor 140 transmits the position of the stylus 120 on the touch surface 160 through the optical images and using the triangulation method. However, although the optical sensor has been placed as close as possible to the touch screen, there is still a gap between the image intercepting surface of the optical sensor and the touch surface. Therefore, although the position of the stylus 120 on the touch surface 160 can be known by the first light source, it is impossible to know whether the stylus 120 has actually touched the touch surface 160.

Therefore, in particular, the stylus 120 is designed such that the touch end of the stylus (such as the tip of the stylus 120) generates a light signal when pressed to the touch surface 160 of the touch panel 150. The light signal is also the second light ray L2 (shown by a dashed arrow in FIG. 1) in the embodiment of the present invention. Therefore, the processor 140 in the optical touch device 110 can detect whether the stylus 120 actually touches the touch panel 150 by detecting the second light L2 or not, thereby assisting in determining the detected signal. Whether the location information is indeed the actual position where the stylus 120 touches the touch surface 160.

2 and 3 are structural views of a stylus pen 120 according to an embodiment of the invention. FIG. 2 illustrates the internal structure of the stylus 120, and FIG. 3 illustrates the external structure of the stylus 120. Referring to FIG. 2 and FIG. 3 , the stylus 120 mainly includes a switch module 210 and a second light source 220 , and further includes a touch end 230 , a power storage device 240 , and a reflective area 310 . The switch module 210 is coupled to the second light source 220. In this embodiment, the switch module 210 is a pressure switch formed by a spring, and the second light source 220 is a light-emitting diode unit that can emit a second light L2 (eg, infrared light). The second light source 220 is mainly disposed at the touch end 230 of the stylus 120. The touch terminal 230 can be a tip portion of the stylus 120 for contacting the touch surface 160. The touch terminal 230 is a transparent material object that encloses the second light source 220 implemented by the infrared light emitting diode unit. When the user holds the stylus 120 and causes the touch terminal 230 to be pressed, the switch module 210 connects the power storage device 240 with the second light source 220, so that the second light source 220 generates the second light L2. In contrast, when the user holds the stylus 120 and has the touch terminal 230 not pressed, the stylus 120 does not generate the second light L2. In other words, the switch module 210 can determine whether the stylus 120 touches the touch panel 150 to cause the second light source 220 to generate the second light L2. The electrical storage device 240 can be a battery.

The reflective area 310 of FIG. 3 is disposed on the body portion of the stylus 120 for reflecting the first light L1 generated by the first light source in FIG. 1 to generate a third light L3, thereby allowing the optical touch of FIG. The control device 110 can more clearly know the location of the stylus 120.

In this embodiment, the first light L1 and the second light L2 may have the same wavelength, for example, all of the infrared light; the first light source and the second light source 220 may be implemented by using a light emitting diode unit that emits infrared light. The second light source 220 is less considered to use a laser light source because the energy required for the laser light source is higher, and the battery 240 carried by the stylus 120 itself has a limited capacity, so there is a problem that the storage power is low.

Specifically, the processor 140 determines whether the estimated touch position is obtained according to the first light L1 received by the optical sensor in the optical module 130. In order to enable the processor 140 of the optical touch device 110 of FIG. 1 to distinguish the third light L1 (the light obtained from the optical sensor in the optical module 130 by the first light L1 reflected by the stylus 120) and the first The difference between the two light rays L2 (generated by the touch terminal 230 of the stylus 120 being pressed), the processor 140 of the embodiment of the present invention uses the first light source to disable the next light of the first light L1 generated periodically. During the period of time, it is determined whether the optical sensor in the optical module 130 has received the second light L2, thereby determining whether the estimated touch position obtained during the last enablement of the first light L1 is indeed the stylus 120. The position in contact with the touch surface 160.

In another embodiment consistent with the spirit of the present invention, the switch module of the stylus 120 of FIG. 1 can also be a push switch instead of the pressure switch shown in FIGS. 2~3. When the user thinks that the touch end of the stylus 120 has touched the touch surface 160 of the touch panel 110 of FIG. 1 , the user can actively press the push switch to generate the second light. . Therefore, the processor 140 of FIG. 1 can determine that the estimated touch position obtained by the first light L1 is indeed the correct touch position of the stylus 120.

4 is a waveform diagram of a pulse width modulation (PWM) signal S1 and a second light L2 for periodically generating a first light L1 according to an embodiment of the invention. Referring to FIG. 1 and FIG. 4 simultaneously, in the embodiment, the first light source is controlled by the PWM signal S1 of the processor 140 of FIG. 1 to generate the first light L1. In other words, when the PWM signal S1 is in the enable period (eg, periods 410, 430, 450), the first light source will generate the first light L1; when the PWM signal S1 is in the disable period (eg, during the period 420, 440) At 460), the first light source is turned off without generating the first light L1. If the processor 140 obtains the third light L3 by the first light L1 during the enablement of the signal S1, the touch signal of the stylus 120 or other touch object is calculated (the touch signal is referred to herein as If the touch position is estimated, there are several possibilities. One possibility is that the touch end of the stylus 120 has touched the touch surface 160, and the second light source generates the second light; the second possibility is The touch end of the stylus 120 has touched the touch surface 160, but the user does not press the push switch of the stylus 120 without causing the second light source to generate the second light; the third possibility is that the touch The pen 120 does not actually touch the touch surface 160.

In order to determine whether the stylus 120 has touched the touch surface 160, the processor 140 determines whether the second light ray L2 is received when the first light source controls the next disable period of the signal S1 of the first light L1. The reason is that if the first light L1 is continuously generated, and the third light L3 and the second light L2 generated according to the first light L1 are both infrared light, the processor 140 cannot distinguish the two. In contrast, when the first light ray L1 is not generated during the disable period of the signal S1, the light obtained by the processor 140 through the optical sensor is the second light ray L2. Here, the waveform diagram of FIG. 4 is described with reference to FIG. 1. If the processor 140 of FIG. 1 obtains the above-mentioned estimated touch position during the enable period 410 of the signal S1, the next disablement of the signal S1 will be performed. During the period 420, it is determined whether the second light ray L2 is received through the optical sensor in the optomechanical module 130 (as indicated by the dashed arrow A). Since the processor 140 does not receive the second light L2 (the second light L2 is disabled) in the next disable period 420 of the signal S1, it indicates that the stylus 120 does not actually touch the touch surface 160, or The user does not press the push switch of the stylus pen 120 without causing the second light source to generate the second light. Therefore, the processor 140 determines that the estimated touch position is not the position touched by the stylus 120 and is discarded.

If the processor 140 of FIG. 1 continues to obtain the estimated touch position during the enable period 430 of the signal S1, it is determined whether the optical sensor in the optical module 130 is transmitted through the next disable period 440 of the signal S1. The second light L2 is received (as indicated by the dashed arrow A2). Since the processor 140 has received the second light L2 in the next disable period 440 of the signal S1 (the second light L2 is enabled), indicating that the stylus 120 has actually touched the touch surface 160, the processor 140 It is determined that the enabling period 430 obtains the position where the estimated touch position is actually touched by the stylus 120, and performs the reporting action according to the estimated touch position, so that the optical touch system 110 implements the touch function.

In this embodiment, the processor 140 sets a brightness detection threshold to determine whether the third light L3 can be used to determine the position of the stylus 120. Since the optical sensor converts the brightness of the light into a grayscale value (range "1" to "255") after obtaining the light, the brightness of the light is up to "255", and the light brightness is at least "1", "0 "There is no light detected. In the embodiment of the present invention, the brightness detection threshold is set to “10”, and the processor 140 in the optical touch device 110 receives the third light L3 that is higher than the brightness detection threshold “10” to detect the stylus 120. s position. In other words, the gray level value of the third light ray L3 is "10" or more, and can be used to determine the position of the stylus pen 120, otherwise it will be discarded. In the embodiment of the present invention, the brightness of the second light L2 can be set to be between gray scale values "2" to "10", and the gray scale values are all smaller than the brightness detection threshold, thereby saving power consumption in the stylus 120.

FIG. 5 is a flow chart of a touch detection method of an optical touch device according to an embodiment of the invention. Referring to FIG. 1 and FIG. 5 simultaneously, the touch detection method is applicable to the optical touch device 110. In step S510, the processor 140 in the optical touch device 110 controls the first light source in the light module 130 to periodically generate the first light L1. In step S520, the processor 140 obtains the third light ray L3 according to the first light ray L1 by using a plurality of optical sensors in the optomechanical module 130. In step S530, the processor 140 determines whether the estimated touch position of the stylus 120 is obtained according to the third light L3 reflected by the first light L1. If the estimated touch position is not obtained, the processor 140 repeats steps S510 to S530 to continuously determine whether the estimated touch position of the stylus is obtained. When the estimated touch position is obtained, the process proceeds from step S530 to step S540, and the processor 140 determines whether to receive the second light L2 during the next disable period of the first light. The second light L2 may be generated when the stylus 120 touches the touch surface 160, or the user may actively press the switch module of the stylus 120 to cause the second light source to generate the second light L2. If the determination in step S540 is no, the process proceeds to step S560 to discard the estimated touch position, and the process returns to step S510 to automatically continue the touch detection method.

If the step S540 is YES, that is, the processor 140 has received the second light L2 during the next disable period of the first light, it is determined that the estimated touch position is the position touched by the stylus 120. The subsequent reporting operation is performed to enable the optical touch system 110 to implement the touch function.

In some embodiments, the steps of steps S540 and S530 may be reversed, that is, first step S540 is used to determine whether to receive the second light L2 during the disable period of the first light L1. If YES in step S540, it means that the position touched by the stylus pen 120 can be obtained during the next enabling period of the first light, and thus the process proceeds to step S530 to obtain the touch position. The order in which steps S530 and S540 can be adjusted according to the needs of the embodiment of the present application can be adjusted.

FIG. 6 is a functional block diagram of the optical touch device 110 of FIG. 1. Referring to FIG. 6 , the optical touch device 110 includes a touch panel 610 , a plurality of optical sensors 620 , a first light source 630 , and a processor 640 . The touch panel 610 , the plurality of optical sensors 620 , and the first light source 630 are similar to the touch panel 150 , the optical sensor in the light module 130 , and the first light source in FIG. 1 . The processor 640 can be provided with a plurality of functional modules, which can be implemented in software or in a hardware circuit. The processor 640 includes a light source generating module 650, a touch position determining module 660, and a contact determining module 670. The light source generating module 650 transmits the first light source 630 to periodically generate the first light. The touch position determining module 660 determines whether the estimated touch position is obtained according to the first light. The contact determination module 670 is coupled to the contact position determination module 660. When the estimated touch position is obtained, the contact determination module 670 determines whether to receive the second light during the next disable period of the first light. The second light may be generated when the touch pen touches the touch surface of the touch panel 610, or the user may actively press the switch module of the touch pen to generate the second light from the second light source. L2. When the second light has been received, the contact determination module 670 determines that the estimated touch position is the position touched by the stylus. For the detailed implementation method of the embodiment of the present invention, please refer to the above embodiment.

In summary, the optical touch system, the optical touch device, and the touch detection method thereof are firstly determined by the first light on the optical touch device to determine whether the estimated touch position is obtained. . After obtaining the estimated touch position, the optical touch device determines whether the stylus actually touches the touch panel by using the second light emitted from the stylus during the next disable period of the first light. The second light may be generated when the stylus touches the touch panel, or may be generated when the user presses the switch module on the stylus. In this way, the optical touch device can detect whether the stylus actually touches the touch panel by detecting the second light or not, thereby assisting to determine whether the estimated touch position is actually touched by the stylus The actual location of the touch. In addition, the brightness of the second light can be adjusted to be lower than a preset threshold of the optical touch device to achieve power saving.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧ optical touch system
110‧‧‧Optical touch device
120‧‧‧ stylus
130‧‧‧ optomechanical module
140‧‧‧ processor
150‧‧‧ touch panel
160‧‧‧ touch surface
210‧‧‧Switch Module
220‧‧‧second light source
230‧‧‧ Touch end
240‧‧‧Electrical storage equipment
310‧‧‧Reflective zone
410, 430, 450‧‧‧Enable period of signal S1
420, 440, 460‧‧‧ The period of disablement of signal S1
610‧‧‧Touch panel
620‧‧‧ optical sensor
630‧‧‧First light source
640‧‧‧ processor
650‧‧‧Light source generation module
660‧‧‧Touch position judgment module
670‧‧‧Contact Judgment Module
S510~S530‧‧‧Steps
A1, A2‧‧‧ dotted arrows
L1‧‧‧First light
L2‧‧‧second light
L3‧‧‧3rd light
S1‧‧‧ pulse width modulation signal

1 is a schematic diagram of an optical touch system in accordance with an embodiment of the present invention. 2 and 3 are structural views of a stylus according to an embodiment of the invention. 4 is a waveform diagram of a pulse width modulation signal S1 and a second light L2 for periodically generating a first light L1 according to an embodiment of the invention. FIG. 5 is a flow chart of a touch detection method of an optical touch device according to an embodiment of the invention. 6 is a functional block diagram of the optical touch device of FIG. 1.

S510~S560‧‧‧Steps

Claims (24)

An optical touch system includes: an optical touch device, comprising: a touch panel having a touch surface; a plurality of optical sensors and a first light source, wherein the first light source periodically generates a first a light source; and a processor coupled to the optical sensor and the first light source; and a stylus comprising a switch module and a second light source, wherein the switch module is coupled to the second light source, wherein When the stylus touches the touch surface, the switch module causes the second light source to generate a second light, wherein the processor determines the first light and the second light received by the optical sensors The location of the stylus. The optical touch system of claim 1, wherein the processor controls the first light source to periodically generate the first light. The optical touch system of claim 1, wherein the second light source is disposed at a touch end of the stylus, and the second light source is a light emitting diode unit. The optical touch system of claim 1, wherein the first light and the second light have the same wavelength, and the brightness of the second light is lower than a brightness detection threshold, wherein the optical sensors Receiving a third light that is higher than the brightness detection threshold to detect the position of the stylus, wherein the third light is the first light reflected from the stylus. The optical touch system of claim 1, wherein the first light and the second light are infrared light. The optical touch system of claim 1, wherein the processor determines whether to obtain an estimated touch position according to the first light received by the optical sensors, and obtains the estimated touch. After the location, the processor determines whether the optical sensors receive the second light during the next disable period of the first light source, and if yes, the processor determines that the estimated touch position is touched by the stylus The location of the touch. The optical touch system of claim 6, wherein the processor does not receive the second light during the next disable period of the first light source, the processor determines that the estimated touch position is not the touch The position touched by the pen. The optical touch system of claim 1, wherein the switch module is a pressure switch. The optical touch system of claim 1, wherein the stylus further comprises: a reflective area disposed on the body portion of the stylus for reflecting the first light. A touch detection method for an optical touch device, wherein the optical touch device includes a touch surface, the touch detection method includes: periodically generating a first light; determining whether the light is determined according to the first light Obtaining an estimated touch position; determining, after the estimated touch position, whether to receive a second light during a next disable period of the first light source, wherein the second light is generated by a stylus When the touch surface is touched; and if so, the estimated touch position is determined to be the position touched by the stylus. The touch detection method of claim 10, further comprising: determining that the estimated touch position is not the touch when the second light is not received in the next disable period of the first light source The position touched by the pen. The touch detection method of claim 10, wherein the stylus comprises a switch module and a second light source, and the switch module is coupled to the second light source. In the touch detection method of claim 12, when the stylus touches the touch surface, the switch module causes the second light source to generate the second light. The touch detection method of claim 12, wherein the second light source generates the second light when the switch module is pressed. The touch detection method of claim 10, wherein the second light source is disposed at a touch end of the stylus, and the second light source is a light emitting diode unit. The touch detection method of claim 10, wherein the first light and the second light have the same wavelength, and the brightness of the second light is lower than a brightness detection threshold, wherein the optical touch The device receives a third light that is higher than the brightness detection threshold to detect the position of the stylus, wherein the third light is the first light reflected from the stylus. The touch detection method of claim 10, wherein the first light and the second light are infrared light. The touch detection method of claim 10, wherein the switch module is a pressure switch. An optical touch device includes: a touch panel having a touch surface; a plurality of optical sensors and a first light source; a light source generating module that controls the first light source to periodically generate a first light source a touch position determining module, determining whether to obtain an estimated touch position according to the first light; and a contact determining module coupled to the touch position determining module, when obtaining the estimated touch position After the second inactive period of the first light source, the contact determining module determines whether to receive a second light, wherein the second light is generated by a stylus when the touch surface is touched, if The contact determination module determines that the estimated touch position is a position touched by the stylus. An optical touch system includes: an optical touch device, comprising: a touch panel having a touch surface; a plurality of optical sensors and a first light source, wherein the first light source periodically generates a first a light source; and a processor coupled to the optical sensor and the first light source; and a stylus comprising a switch module and a second light source, the second light source when the switch module is pressed A second light is generated, wherein the processor determines the position of the stylus according to the first light and the second light received by the optical sensors. The optical touch system of claim 20, wherein the processor determines whether an estimated touch position is obtained according to the first light, and after obtaining the estimated touch position, the processor is in the first Determining whether to receive the second light in a next inactive period of a light source, wherein the second light is generated by a user pressing the switch module to cause the second light source to generate, and if so, the processor determines the estimate The touch position is the position touched by the stylus. The optical touch system of claim 20, wherein the switch module of the pen is a push switch. A touch detection method for an optical touch device, wherein the optical touch device includes a touch surface, the touch detection method includes: periodically generating a first light; determining whether the light is determined according to the first light Obtaining an estimated touch position; determining, after the estimated touch position, whether to receive a second light during a next disable period of the first light source, wherein the second light is by a stylus The switch module is generated when pressed; and if so, the estimated touch position is determined to be the position touched by the stylus. An optical touch device includes: a touch panel having a touch surface; a plurality of optical sensors and a first light source; a light source generating module that controls the first light source to periodically generate a first light a touch position determining module, determining whether to obtain an estimated touch position according to the first light; and a contact determining module coupled to the touch position determining module, when obtaining the estimated touch position The contact determination module determines whether to receive a second light during the next disable period of the first light source, wherein the second light is generated when the switch module of the stylus is pressed, and if so, The contact determination module determines that the estimated touch position is a position touched by the stylus.